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  • pg_control文件的作用

      记录了pg服务器内部的信息,如最新检查点时间、服务器状态、WAL文件位置,总之和数据库可能损坏相关的信息这里都有维护,还包括LC_CTYPE/LC_COLLATE等信息,和oracle控制文件差不多的。如果该文件被删除,实例将无法启动。运行时,会在共享内存中维护一份pg_control的镜像。

      https://blog.csdn.net/lixiaogang_theanswer/article/details/114933301

    查看pg_controldata文件的内容

      有两种方式,一种是通过SQL查询,如下:

    select * from pg_catalog.pg_control_checkpoint();
    select * from pg_catalog.pg_control_system();
    select * from pg_catalog.pg_control_init();
    select * from pg_catalog.pg_control_recovery(); 

      还有一种是通过命令行。如下:

    [postgres@hs-10-20-30-194 global]$ pg_controldata ../../data
    pg_control version number:            1300
    Catalog version number:               202105121
    Database system identifier:           6965242430856727465
    Database cluster state:               shut down
    pg_control last modified:             Tue 25 May 2021 01:10:07 AM CST
    Latest checkpoint location:           17/7C6E96E0
    Latest checkpoint's REDO location:    17/7C6E96E0
    Latest checkpoint's REDO WAL file:    00000001000000170000007C
    Latest checkpoint's TimeLineID:       1
    Latest checkpoint's PrevTimeLineID:   1
    Latest checkpoint's full_page_writes: on
    Latest checkpoint's NextXID:          0:46350725
    Latest checkpoint's NextOID:          16818
    Latest checkpoint's NextMultiXactId:  1
    Latest checkpoint's NextMultiOffset:  0
    Latest checkpoint's oldestXID:        727
    Latest checkpoint's oldestXID's DB:   1
    Latest checkpoint's oldestActiveXID:  0
    Latest checkpoint's oldestMultiXid:   1
    Latest checkpoint's oldestMulti's DB: 1
    Latest checkpoint's oldestCommitTsXid:0
    Latest checkpoint's newestCommitTsXid:0
    Time of latest checkpoint:            Tue 25 May 2021 01:09:54 AM CST
    Fake LSN counter for unlogged rels:   0/3E8
    Minimum recovery ending location:     0/0
    Min recovery ending loc's timeline:   0
    Backup start location:                0/0
    Backup end location:                  0/0
    End-of-backup record required:        no
    wal_level setting:                    replica
    wal_log_hints setting:                on
    max_connections setting:              10000
    max_worker_processes setting:         8
    max_wal_senders setting:              10
    max_prepared_xacts setting:           0
    max_locks_per_xact setting:           64
    track_commit_timestamp setting:       off
    Maximum data alignment:               8
    Database block size:                  8192
    Blocks per segment of large relation: 131072
    WAL block size:                       8192
    Bytes per WAL segment:                16777216
    Maximum length of identifiers:        64
    Maximum columns in an index:          32
    Maximum size of a TOAST chunk:        1996
    Size of a large-object chunk:         2048
    Date/time type storage:               64-bit integers
    Float8 argument passing:              by value
    Data page checksum version:           0
    Mock authentication nonce:            11d5c8d76b72e3c68abe49250c775aa8a0a5e50ec275757b002b74d9547674d0

       pg_control控制文件中的内容由ControlFileData定义,在initdb初始化时创建。

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  • 原文地址:https://www.cnblogs.com/zhjh256/p/14808608.html
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